Herbicide should control pesky Bermuda grass

May. 6, 2006 12:00 AM

Question: For the better part of two years, a disability prevented me from working in a small flower garden in my back yard. Bermuda grass grew into the garden and now that I again am able to get down to work in it, I have been battling that blasted grass. Is there anything I could plant to choke out the grass? If there isn't a plant to do the trick, is there any way to kill the grass without injuring the grass in the lawn outside the planter? The planter is ringed by a single layer of those manufactured "bricks" found at Home Depot. Would adding a second course of blocks (making a deeper planter) help the problem?

Also, I have a purple-leaf plum tree that resembles the ribs of an umbrella blown inside out. Everything just sticks straight up in the air. It has been in the ground for about 1 1/2 years and is growing taller, but will it ever branch out into a nice canopy? If not, is there anything I can do to encourage this development?

- Maryln Inman, Mesa

Answer: I'm not aware of any plant that will choke out Bermuda. It's a tough grass that survives our harsh heat and is desirable as a lawn. But as you have discovered, it can take over garden beds. Yanking out Bermuda grass by hand is not always effective because the grass spreads by producing underground runners that take root and produce new plants, with the new plants producing runners, and so on.

You can use an herbicide containing the funny-sounding chemical fluazifop, which kills only grass and will not harm landscape plants. Grass-B-Gon by Ortho is one product that contains fluazifop.

You also can spot-kill Bermuda grass inside the planter by using an herbicide that contains glyphosate, such as Roundup by Monsanto. First, water the grass and apply the herbicide while the grass is growing. You have to be careful not to spray this herbicide on any other plants, because the chemical will kill them. One trick is to take a piece of poster board or cardboard and use it as a spray barrier between the plants you want to protect and the grass you want to kill. Wait a few days after applying the chemical and water the treated area again. If grass still is growing, apply more herbicide. You may have to repeat the process several times.

Border the lawn with a solid concrete/concrete-brick border and have a dirt or rock buffer zone outside the border that is not watered.

As for your purple-leaf plum, it grows like that. It is a vase-shaped tree reaching 20 to 30 feet in height and about 12 feet in canopy width. It should be pruned yearly to thin out branches that cross and to remove suckers. Purple-leaf plum, which produces lovely fall color, is one of the first trees to bloom in the spring, and is recommended for planting under power lines.

Virtual garden: The Water - Use it Wisely campaign offers tips for "summer-scaping" on its Web site, wateruseitwisely.com. In addition, the site has an interactive watering guide for turf, xeriscape plants and trees.

A campaign tip: Proper watering year-round improves the odds of plant survival. By watering deeply and less frequently, roots grow deeper into the soil, where they are better buffered from the heat and sun.

A greener thumb: The sixth annual Bisbee Bloomer Garden Tour will be held Sept. 9, rather than in May as in years past.

This year's tour will feature nine gardens in historical Old Bisbee, music and painting. The tour date has been moved because of an extremely dry spring, according to Fred Miller, president of the Bisbee Bloomers.

Tickets are $9 for the tour, with an additional $1 for shuttle-bus tickets.

Tickets may be purchased at the Bisbee Visitor Center, at No. 2 Copper Queen Plaza, or at a day-of-the-event table in front of the Bisbee Mining & Historical Museum.

Send garden-related questions, Web site suggestions and tips to Southwest Gardens, in care of Diana Balazs, The Arizona Republic Scottsdale Bureau, 16277 Greenway-Hayden Loop, Suite 200, Scottsdale, AZ 85260; via e-mail to diana.balazs@arizonarepublic.com; or via fax to (602) 444-6875. Include your full name and the city you live in and a telephone number. Your number will not be published.